Posthole digger



Feb. 18, 1947. w. G. z lMMRLEiN ETAL 2,416,036

POST HLE DIGGER Filed Deo. 11, 1944 v 4 sheets-sheet 1 Feb. 18, 1947. w.G. ZIMMELEIN .ET AL POST HOLE DIGGER 4 sheets-'sheet 2 A Filed Dec. ll,19.44

3mm d Wlm @Zi/Myriam Feb. 18, 1947. w.G.z1MMERLlEiN ET AL POST HOLEBIGGER Filed Dec. 1-1, 1944 4 Sheets-Sheet 3 Feb. 18, 1947.. w. G.zlMMERLElNET A1. 2,416,036

PosT HOLE DIGGER Filed Dc.v 11, 1944 4 sheets-sheet 4 Patented Feb. 1s.194':`7I

ros'rHoLE BIGGER 'Y William' G. Zimmerlein and Le Roy C. Siebert,

Mendota, Ill. v

Application December 11, 1944, Serial No. 567,584

The present invention relates.v to improvements in post hole diggers,and has for an object to provide a power augur applicable to aconventional form of tractor without involving any essentialmodification in the tractor, but so arranged and constructed as to bemanufactured separately from the tractor and mounted thereupon byunskilled labor.

Another object of the invention resides in providing a post hole diggeror the like in which a novel form of drive 'mechanism is provided forthe augur with the source of power developed from the tractor engine,and with the control of the apparatus governed by the operator of thetractor from the usual seat upon such tractor.

ft is a further object of the invention to provide a tractor-equippedpower augur in which a novel form of driving mechanism is constructedand arranged to drive the augur shaft down a predetermined distance andsubsequently and automatically, after the work is done, to raise suchshaft together with the augur, through a distance which will elevate theaugur completely from the hole at which time a further automatic devicecomes into play for throwing the driving mechanism into a neutralpo-sition where all axial motion of the augur shaft is arrested.

A still further object of the invention is to provide a novel form ofdifferential in combination with a-braking mechanism by which the feedof the augur shaft is achieved, governed as to its longitudinaltraverse, and automatically stopped after completing its cycle ofmovement with the digging of the hole and the removal of the augurtherefrom to an initial position raised clear of the ground to enablethe tractor to pursue its way to the next objective.

1 A still further object of the invention is to provide a drivingmechanism for earth augurs and the like swivelly mounted from a tractoror other oase support to enable the axis of the augur to be inclined ortilted as may be required in the `formation of vertical holes or holesangularly VAshaft in the raised position out of the ground.

11 Claims. (Cl. 2557-22) Figure 5fis a top planview of the mechanismwith the parts as shown in Figure 3, and

Figure 6 is a vertical section taken through the' driving mechanism.

Referring mo-re particularly to the drawings and rfor the present toFigures l to 6, l0 designates a power drive shaft driven by a belt IIengaging a pulley I2 on said shaft lo, the belt Il being driven from thecustomary power takeoff shaft of the conventional farm tractor which isdesignated generally at I3.

VThis power drive shaft is journaled through a sleeve I4 supported inbearings I5 and I6 mounted upon the front frame portion of the tractorI3 in such manner that the axis of the power drive shaft lil istransverse of the vehicle.

The sleeve I4 may be an extensionof the gear case which is composedpreferably ofthe two halfV sections Il, I8 bolted together or otherwisesuitably connected. This gear case houses a differential mechanism andsupports a power drive for the augur .I9 and the augur drive shaft 2Bwhich is threaded throughout its entire orV a major length for thepurpose of being fed up and down through a feed nut 2|. This feed nut 2|has no axial travel but is rotatable to feed the Vshaft 2i downwardlytherethrough by the differential mechanism; or at another stage is heldstationary whiley the shaft 20 is rotated by the differential mechanismto cause the shaft and the entrained augur I9 to rise through thestationary nut 2 I.

The nut 2l is made fast by a spline 22 or otherwise to the hub 2.3 of anupper brake drum 24. This brake drum 24 is restrained against downwardor axial movement by a flange 25 which may be a part of the uppersection I8 of the gear case, being connected with that section through ahollow neck 26.v

2,41 epee Y radial studs 3i carried in the differential rotary ring orspider 32. This spider 32 is affixed to rotate to the differential ringgear 33 by the bolts or other mounting means 34. The ring gear 33 isbeveled to mesh with the bevel pinion 35 on the power drive shaft IQ.

Opposed to the upper sleeve gear 213 is a lower sleeve gear 3B, alsobeveled and meshing with the planetary gears Gear 36 is afxed to theupper end of lower sleeve 31 which extends downwardly from theV lowersection ofthe gear case I1. The lower hollow neck 33'of the gear casehouses the lower sleeve 31 and terminates in a lower flange 35. Thescrew shaft 2.5 Aextends through the smooth bore of lower sleeve 31..The lower sleeve 31 carries an inwardly projecting keyj 43 kwhichenters a longitudinal keyway or slot 4l of the screwshaft 23; Thus thescrew shaft 25 and lower sieeve 31 are constrained by key 4B to alwaysrotate in unison but' the longitudinal key- `way tl permits of relativeaxial movement of screw shaft 23 down and up through sleeve 31.

Lower sleeve 31 projects below lower flange 39 and receives thereon thehub 42 of the lower brake drum 43, therebeing a key or spline 411locking the sleeve 31 to the hub of the brake drum 43.

From a comparative View point, while the lower sleeve 31 may have norelative rotation with respect to the augur screw shaft 23, and whilethe screw shaft 2i) may execute both up and down movements relativelythrough the sleeve 31, the upper sleeve 21 has no direct connection withthe screw shaft 2G, such'screw` shaft 20 being both slidable axially androtatablein the "smooth bore of the sleeve 21,A `In this connection itshould be noted, however, that the nut 2l is but an extension orprolongation of the upper sleeve 21,Y both sleeve '21 and nut 2l beingconfined against relative travel in either anfaxial or rotational sense.To put the matter another way, the internal threads of the nut 2l mightbeV continued all the way down through the interior ofthe sleeve 21withoutaffecting the construction andmode of operation of the device. Y.i Y

The two i'la'nges 25 and 39` act as mutual supports and stops topreventendwise movement of the sleeves 21 and 31 and ofthe partsconnected thereto, inasmuch as the upper and lower brake drums 24 and 43are affixed to ,their respective sleeves 21 and 31. i

Upper and lower stop collars 45 and '45 are provided on the screw `shaft25, the upper collar being'slidable and adjustable axially oi the screwshaft and affixed in its adjusted position by means of a set screw 41 orother convenient device.

The arrangement is such that the entire driv mechanismas a unit mayrotate about the vhori# zontal axis of the power drive shaft l0. Forthis purpose a suitable handle is'aixed to and projects radially fromthe sleeve I4. By angularly turning the handle 48 thesleeve I4 and thegear case and all of the parts contained therein may be correspondinglyrotated or angularly adjusted to any angle at which the augur 19"'isfange 25.

v,oi a link 52.

circumierentially from the external cylindrical braking surface of thedrum 24. One end 5| of the brake band te is turned radially outward vandaxed to a stationary guide member 52.

This guide member has a part extending down beyond the edge or" theupper gear case flange 25 beingr adixed, as indicated at 'B8 beneathsuch The outturned brake band edge 5l and guide member 52 are perforatedto slidingly receive an' end portion of a brake rod 53 which may'substantially parallel a tangent of the circular upper brake drum 24.rIhe other outturned free end 54 of theupper brake band 49 is affixedtothe brake rod 53 as bythreading the same int-o a threaded perforationof the end 54 with the nut acting as a jam or lock nut adapted tobefturned up against the terminal part 54. However, this connection maybe made in any desired manner. A coil spring 55 of'a desired number ofconvolutions envelopes brake rod 53 between the two ends 5l and 54 ofthe brake band 45. This spring is an expansive spring, normally abuttingagainst stationary-guide member 52 and urging the free end 54 of thebrake band 49 into vloose or open position about the brake drum 24.

The other or left hand end of the brake rod 53 is biurcated, asindicated at 51 to receive an upstanding support 53 to which it ispivoted by the pin 53. The support 58 is carried upon a swinging havinga iulcrum or pivotal point Si vupon the lower side of the upper gearcase iange 25.

The pin 53 also'provides a pivot for an end Such link 62 has a pivot 63engaged withfits intermediate portion, the part 6 2a of the link to theleft of the pivot 63 having a stop finger 65 projecting outwardly fromits lower edgeiniposition to encounter the lower side ci a shaft G5. Thepin 63 also engages an arm 55 pinned, as indicated at 51, or otherwiseaffixed to the shaft 65. The links 62 and 66 together" constitute atoggle lever connecting shaft $5 and brake rod 53 with the tailpiece $2aof lever 63 andits ,nger Se acting to arrest the upward movement of thetoggle lever when the three pivots 53, 53 and 65 get into substantialalignment or when the central pivot 63 gets just slightly above the lineconnecting the centers of the twc'pivots 53 and 65.

` An arm't turning loosely about the shaft 55 has atail piece 699 with astop iinger 10 projecting from the upper edge thereof in positiontojengage theupper side of the pivot 63.

VThe shaft 55 is jlournaledto rock in the upper portions oi Yverticallydisposed members 1l and 12 of a frame which straddles a crosssectionally square portion la of the sleeve i4 and may be affixedthereto by the bolts or other fastenings 113. Between the frame members1l and 12, the shaft 65 carries an operating arm 14, an angle trigger`arm 15 and a throw vout arm 15, which latter carrod link 8| extendingdown to a point belowthe lower brake drum 43 where it is pivoted, as at82, to the longer arm 83 of a bell crank aiXed to a shaft 84 journaledin the lower portions of the frame bars ll, '12. The shorter arm 85 ofthe bell crank is pivoted at 96 to an end of a link 8'I, the other endof which is pivoted at 88 to an end of a brake rod 89. The lower brakeband 99 encompassing the lower drum 43 and supported upon the ledge 9|thereof has its outturned ends perforated to receive therethrough thebrake rod 89. One end 9| of the brake band 99 is anchored to thestationary guide 92 through which the brake rod 89 freely slides. Suchstationary guide is affixed, as at 93, to the upper surface of the lowergear case flange 39. A spring helix 94 is wound about brake rod 89 andabuts against the stationary end SI of the brake band 99 and a pair oflock nuts 95 mounted on the right hand end of the brake rod 89, thespring 94 biasing Ibrake rod 89 to a right hand thrust. The free end ofbrake band 99 is turned outwardly as indicated at 96 and coupled to thebrake rod 89 as by screw threading. The threaded portion of the brakerod 89 may also carry nut 91 to exert the necessary thrust against thefree end of the brake band 99. A trigger arm 98 is affixed as at 99 tothe shaft 84 between the frame members il, 72 in a position in the pathof movement of the tripping disc 46 which is carried by the augur shaft29. The operating arm 'I4 is connected by a chain I9I or other flexibleconnection to a point convenient to the operator of the tractor.

In operation the tractor engine through the belt connection II drivesthe shaft I9 and the bevel gear 35 in the differential casing. The ringgear 39 is consequently continuously rotated and this ring gear rotatesfreely in the gear case. It carries around with it the planetary pinions38 which normally do not rotate about their studs 3| but exert4 equalpressure upon the bevel sleeve pinions 29 and 36 to rotate the samesimultaneously in the same direction thus rotating the sleeves 2l and 3lin the same direction. Due to the spline 49 the rotating lower sleeve 31carries the augur shaft 29 around with it. At the same time the uppersleeve 2l carries the nut 2| around with it. Thus augur shaft 2! and nut2| rotate simultaneously at the same rate of speed and therefore theshaft 29 has no axial travel.

When its brake yband 49 is tightened about the upper brake drum 24, therotation of nut 2|, upper sleeve 2l and its pinion 29 is arrested butthe rotation of the lower sleeve 31 continues due to the fact that theplanetary gears 30 now rotate about their studs 3|. Rotation of thesleeve 3l through spline 49 causes continued rotation of augur shaft 29.In other words the screw shaft '29 rotates relatively to the nowstationary nut 2| which entails a feeding of the shaft and the augur I9downwardly. Thus the augur I9 is rotated and fed downward simultaneouslyto cause it to enter the ground and bore the necessary hole.

At the completion of the boring operation, the action is automaticallysuspended as hereinafter described and the upper brake is released whilethe lower brake 43, 99 is set. Due to the brake drum 43 being keyed at44 to sleeve 31 and sleeve 37 keyed at 49 to screw shaft 2D, the settingof the lower brake discontinues the rotation of the shaft 29, but therelease of the upper brake causes the resumption of the rotation of nut2| in the same direction, causing the feeding of the shaft 29 and augurI9 upwardly-which action. is

. 6 permitted by the groove 4I of shaft 29 sliding up over the key 48.

The lower tripping disc 49 may be fixed upon the screw shaft 20 so thatit will trip the trigger 98 always at the same time interval withreference to the length of the screw shaft 29; or in other words so soonas the lower end of the augur I9 has sufliciently cleared the groundline to enable the tractor to move forward to a new position withoutsuch augur encountering obstructions or being subject to breakage.

However, the upper tripping disc 45 may be set at various positionsalong the screw shaft 29 as to give the shaft 28 and the augur I9 arelatively greater or lesser traverse before the disc 45 contactstrigger l5.

Figure 2 shows the augur position of the parts in which the toggle lever92, 99 is broken downwardly at its intermediate joint S3, thus leavingthe brake spring 96 unhampered to expand and open the brake band 49.This permits rotation of the upper brake drum 24 and the nut 2| alongwith the sleeve 2l and sleeve gear 2S.

Figure l shows the neutral position of the parts. In the position shownin Figure 1 the augur I9 is raised above the ground and the tractor I3may proceed to a selected locality. Here the operator pulls upon thechain IIII to rock the starting lever T14 from the position shown inFigure 1 to that shown in Figure 3. The movement of the starting lever'I4 rocks the shaft 65 and the arm '59, causing pin 'Il to rock thetrigger l5 into the raised operative position shown in Figure 3.

The movement of starting lever 'I4 and shaft 95 also lifts arms 99 andthe pivot 93 of the toggle lever lifting therewith the other member 62of such toggle lever until the limit finger 94 strikes beneath shaft 95.In other words the toggle 92, 99 is straightened out pushing brake rod53 to the right against the influence of spring 56 and setting the upperbrake which locks the nut 2| against rotation.

In rising the intermediate toggle pintle 93 carries upwardly therewiththe finger 'i9 thus rocking the lever 99, 99a, which pushes down uponthe link rod 9| and counter clockwise rotates bell crank 83, 95, thuspulling to the left on the link 8l and releasing the lower brake 39, 99.

With the upper brake set and the lower brake released, the nut 2| isheld stationary and the screw shaft 29 rotated downwardly therethrough.This is the working action of the augur I9 in penetrating the ground.

The stop collar or disc 45 having been previously set upon the screwshaft 2o at a height above trigger 'i5 corresponding to the depth ofaugur penetration wanted, when the post hole is dug and completed, thestop disc 45 will have oo arrived at trigger le and rocked it to theposition shown in Figure 2. Due to the pin *Il the trigger 'i9 willconsequently also rock arm 19,

shaft 95 and starting lever 'I4 back into the initial position shown inFigure 2. The clockwise 65 rocking of the shaft 65 breaks the togglelinks 69,

62 downwardly to release brake rod 53 to the opening action of itsspring 59. The dierential thereupon promptly resumes the rotation of thenut 2 I. In opening the toggle, the toggle central 70 pivot 93 willsimply retire downwardly from the finger l] without acting to rotate thelever 99,

69a which is loose on the shaft 95. However, as

soon as the restraint of the central toggle pivot 93 is withdrawn, thelower brake spring 94 will expand applying the brake 39, 90 and drawingAupon link 81 in a right hand direction, accompanied by clockwiserotation of bell crank 83, 85, the upward movement of the link rod 8iand the rocking of the lever 69, 63a from the horizontal position oflFigures 1 and 3 to the diagonal position of Figure 2. This is alsoaccompanied by the movement of the lower trigger S8 down to theoperative position shown in Figure 2.

With the upper brake released the nut 2i turns and with the lower brakeset the screw shaft 2 is restrained from rotation. Thus the rotating nut2l feeds the non-rotating screw shaft 2l upwardly raising the augur i9out of the hole. When the stop disc or collar 4B engages trigger 98, theparts will be moved to the neutral position shown in Figure l in whichthe trigger @t has counter clockwise rotated shaft 8d, and in so doinghas released the lower brake S9, Bil without setting the already openupper brake 2d, te.

The rotation of the shaft 8 pulls down upon rod 8| and rotates level1EQ, tts from the position of Figure 2 to that of Figure l. The lever 69,69 being loose on shaft t5, such movement of the lever will not affectthe shaft nor the toggle 62, t6 which remains in the downwardly brokenpositions of Figures 2 and l. Thus both brakes are released. With bothbrakes open, the nut 2l and screw shaft 2li rotate together which has noeffect other than to rotate the already raised augur.

The parts are now in neutral position as shown in Figure l, the tractormay be moved to a new position and the starting lever l swung over toinitiate the same cycle of operations.

As shown in Figures 4 and 5 the frame 1l, 12 may be utilized for itsgreat leverage in rotating the gear case and other parts about the axisof the shaft it in order to change the angle at which the augur I9enters the earth. To conveniently do this a rod 48 is attached to one ofthe frame members 'il and if desired the frame members may be of angleiron construction or flanged, as shown in Figures 4 and 5, toaccommodate the connection of the rod or link Q8. This rod or link 13.8may extend to a lever fulcrum on the tractor near the drivers seat butthis construction is not illustrated as it forms no part of theinvention, it being understood that any suitable arrangement may beutilized to rock the gear case through the desired angle.

t is obvious that various changes and modiilcations may be made in thedetails of construction and design of the above specifically describedembodiment of this invention without departing from the spirit thereof,such changes and modifi-- cations being restricted only by the scope ofthe following claims.

What is claimed is:

1. A post hole digger or the like comprising an augur and augur screwshaft, a rotary nontraveling nut on the shaft, a differential fordriving both the nut and shaft, a normally-open brake for the nut driveof the differential, a normally-set brake for the shaft drive of thediiferential, setting means for the nut brake, release means for theshaft brake, one-way connecting means for operating the release meansfollowing the operating of the setting means but not aifecting the openposition of the setting means when the release means is operated, manual means to initiate the cycle by operating said setting means to setthe nut brake and thus through said connecting means to operate therelease means to permit rotation of the screw shaft through thestationary nut, trip means 8 between the shaft and setting means foropening the setting means, and trip means between the shaft and releasemeans for opening the release means 2. A post hole digger or the like asclaimed in claim l in which said setting means for the nut brakecomprises a toggle-lever with means for arresting the straighteningmotion of the lever when the central pivot is on dead center or slightlypast the dead center position.

3. A post hole digger or the like according to claim l characterized bythe fact that the setting means is comprised of a toggle lever with acentral projecting pivot, said projecting pivot positioned to actuatesaid connecting means in one sequence as heretofore set forth and freeto move away from said connecting means in the breaking or openingmotion of the toggle lever without affecting vsaid connecting means.

4. A post hole digger or the like as claimed in claim l wherein saidrelease means for the shaft brake comprises a bell crank lever havingone arm secured to said connecting means and the other arm coupled tothe shaft brake, the last named trip means being connected to saidlever.

5. A post hole digger or the like according to claim 1 in which thesetting means comprises a toggle lever, a shaft for operating saidtoggle lever on which one member of the toggle is fast, the other memberof the toggle having a tail piece with stop means for engaging saidshaft in the straight position of the toggle lever.

6. A post hole digger or the like according to claim 1 wherein thesetting means comprises mutually pivoted toggle arms one of said armspivoted to the brake rod of the nut brake at a point where such brakerod is carried upon a swivel support.

7. A post hole digger or the like according to claim l wherein a rockshaft operated by a manual starting means is positioned and connected toactuate said setting means and through said connecting means tosimultaneously actuate said release means to set the nut brake andrelease the shaft brake, said connecting means comprising a lever freeon said shaft and having a tail piece with a finger in the path of andoperated by the intermediate pivot of the toggle lever which forms partoi the setting means.

8. A post hole digger or the like according to claim 1 in which thesetting means comprises two mutually pivoted links adapted to breakdownwardly and forming a toggle lever with one link having a tail pieceand the stop nger projecting therefrom, a brake rod of the nut brakepivoted to the free end of the link having the tail piece, a swingingsupport for such pivot joint, a shaft to which the other link is aixedpositioned to be engaged by said stop nger when the toggle pivots havepast dead center, starting means to rotate said shaft in the directionto straighten the toggle links and apply the nut brake, the centralmovable pivot of said toggle lever projecting laterally from said links,said connecting means comprising a lever loose on said shaft having atail piece with said finger projecting above and in the path of saidcentrally projecting pivot.

9. A post hole digger or the like as claimed in claim l in which saidrst named trip means comprises a longitudinally adjustable stop memberon said augur screw shaft, and a rotatable trigger member positioned tobe engaged and moved by said stop member, and connections between saidtrigger member and setting means to cause opening movement of thesetting means and nut brake when the trigger means is moved by said stopmember.

10. A post hole digger or the like according to claim 1 in which saidsetting means comprises a shaft, starting means for rotating said shaft,a link affixed on said shaft, a second link pivoted to the rst link toform a toggle lever and also pivoted to the brake rod of the nut brake,said first named trip means comprising an arm fixed on said shaft havinga pin thereon, a trigger loose on said shaft in the path of said pin,and stop means on the upper portion of the augur shaft adapted to engagesaid trigger.

11. A post hole digger or the like according to claim 1 in which saidlast mentioned trip means comprises a xed stop member on the screw augurshaft in combination with a trigger in the REFERENCES CITED Thefollowing references are of record in the le of this patent:

UNITED STATES PATENTS Number `Name Date 1,873,404 Hild Aug. 23, 19321,887,172 Smith et al Nov. 8, 1932 2,273,203 Keene et al Feb. 17, 19421,668,885 Barnes May 8, 1928

